Internal combustion engine with silencing means

ABSTRACT

In an internal combustion engine of the type having a closed cooling air conducting system associated with the engine cylinder or cylinders, a cooling air blower in the system, sound muffling means associated with the system, and an air filter through which combustion air is introduced to the cylinder or cylinders, long sound deadening channels are provided without a simultaneous increase in the overall constructional size of the engine. The inlet side of the conducting system is made of a maximum length utilizing the free space which is available on the outer sides of the engine, the filter is fastened from the exterior to a wall of the conducting system to receive air from the interior of the conducting system, the suction tube of the cylinder or cylilnders is arranged within the conducting system to communicate with the discharge of the air filter, and the exit side of the conducting system is made of maximum length by utilizing the free space available at the outer side of the engine, and surrounds the exhaust conduit of the cylinder or cylinders.

[ Dec. 16, 1975 1 INTERNAL COMBUSTION ENGINE WITH SILENCING MEANS [75]Inventors: Ernst Hatz, Ruhstorf; Johann Schmuck, Feilnbach, both ofGermany [73] Assignee: Motorenfabrik Hatz KG, Ruhstorf,

Germany 22 Filed: Nov. 4, 1974 21 Appl. No.: 520,825

Related US. Application Data [62] Division of Ser, No. 358,337, May 8,1973.

[30] Foreign Application Priority Data May 8, 1972 Germany 2222556 June15, 1972 Germany 7222447 [52] US. Cl. 123/41.68; 123/4162; 123/4180FOREIGN PATENTS OR APPLICATIONS 118,489 2/1900 Germany 1. 123/4168690,498 4/1940 Germany 123/418 804,502 7/1949 Germany 123/4168 PrimaryExaminer-Charles J. Myhre Assistant Examiner-Daniel J. OConnor Attorney,Agent, or FirmLarson, Taylor & Hinds [57] ABSTRACT In an internalcombustion engine of the type having a closed cooling air conductingsystem associated with the engine cylinder or cylinders, a cooling airblower in the system, sound muffling means associated with the system,and an air filter through which combustion air is introduced to thecylinder or cylinders, long sound deadening channels are providedwithout a simultaneous increase in the overall constructional size ofthe engine. The inlet side of the conducting system is made of a maximumlength utilizing the free space which is available on the outer sides ofthe engine, the filter is fastened from the exterior to a wall of theconducting system to receive air from the interior of the conductingsystem, the suction tube of the cylinder or cylilnders is arrangedwithin the conducting system to communicate with the discharge of theair filter, and the exit side of the conducting system is made ofmaximum length by utilizing the free space available at the outer sideof the engine, and surrounds the exhaust conduit of the cylinder orcylinders.

3 Claims, 7 Drawing Figures US. Patent Dec. 16, 1975 Sheet2 0f23,926,155

INTERNAL COMBUSTION ENGKNE WliTH SILENCING MEANS This is a division ofapplication Ser. No. 358,337 filed May 8, 1973.

This invention relates to internal combustion engines which have aclosed cooling air conducting system including a cooling air blower,which have sound-muffling means associated therewith, and in whichincoming air is passed through an air filter.

In air-cooled internal combustion engines there is always a problem ofreducing the dissemination of noise which is set up in the parts of theengine, and it has been sought to accomplish this by noise-deadeningexpedients, for example by the use of channels lined with rock wool orthe like arranged upstream and downstream of the noise-engendering partsof the engine. To obtain an acceptable degree of sound suppression thechannels equipped with noise-deadening expedients (the so-calledmuffling passages) must not be below a minimum size. To increase theefficiency the aforesaid passages are simply extended in length. This,however, leads to a substantial increase in the constructional size ofthe engine.

It is an object of this invention to provide a sounddeadeningarrangement which permits a substantial effective increase in the lengthof the sound suppression channels without a simultaneous increase in theoverall constructional size of the engine, and moreover whichsimultaneously deadens noise in the cylinders, the blower, and thesuction or exhaust elements of the engine.

In pursuance of this object in accordance with the present invention weprovide an internal combustion engine comprising an engine blockincluding at least one combustion cylinder with at least one airadmission port and at least one gas exhaust port, a closed cooling airconducting system associated with said cylinder, a cooling air blower insaid system, sound-muffling means associated with said system, and anair filter through which combustion air is introduced to said cylinder,characterised by the fact that the said con ducting system comprises airadmission and air discharge ducting sections arranged respectivelyupstream and downstream of said cylinder and externally of the engineblock; the air filter is mounted on the engine block for access from theexterior of the latter and has an air admission and air dischargeducting sections and an air discharge port communicating with a suctiontube connected to the admission port of said cylinder; and the cylinderhas an exhaust conduit connected to said exhaust port and disposedwithin the air discharge ducting section.

In the case of internal combustion engines with aligned cylinders, inaccordance with a special feature of the invention thefree spaceavailable in the engine is utilised to a maximum extent by making theair admission ducting section in the form of an elongated tube which isdisposed laterally of and along the row of cylinder heads. If inarrangements of this character a flywheel is provided on the crankshaft,in accordance with a preferred embodiment of the invention the said tubehas an air admission opening at the side of the engine block at whichthe flywheel is disposed, and an air filter is incorporated in thecooling air conducting system, being fastened in horizontal dispositionto a wall of the conducting system at the same side of the engine blockas the flywheel.

In single-cylinder internal combustion engines the elongation of themuffling passage now sought is obtained in accordance with a feature ofthe invention in a very satisfactory fashion by making the air admissionsection in the form of tubular ducting which is disposed round saidcooling air blower in spiral or volute form. It is advantageous in thiscase to arrange that said tubular ducting is provided with an airadmission port substantially at the uppermost part thereof, and an airfilter is disposed upright in the cooling air conducting system in awall of the latter adjacent the head of the cylinder. In this event theair will be drawn in at an elevated position and, despite the air filteremployed, no installation space is wasted.

A likewise very compact and efficient elongation of the conduit systemat the discharge side is obtained, in conformity with a further featureof the invention, by making the air discharge ducting section in theform of a flat channel which extends approximately parallel to theengine cylinder and is open at the bottom.

In accordance with a particularly advantageous feature of the invention,a cyclone separator or other contaminant-removing means is disposed inthe cooling air conducting system upstream of the air admission port ofthe air filter. The means for removing contamination do not then take upadditional installation space and a further favourable compactness isachieved.

Advantageously the inner walls of the cooling air conducting system arefurnished with at least one layer of rock wool as a sound-deadeningmedium. This layer is advantageously held in the requisite positionagainst the wall by means of a covering sheet of mesh or perforatedplate so that these layers will not interfere with the functioning ofthe apparatus. Further, the cooling air blower will likewise be linedwith a layer of rock wool for the purpose of providing additionalsounddeadening at the wall of the housing thereof.

A further and notable increase in the sound-deadening effect is achievedin accordance with a further feature of the invention if the airadmission ducting section and/or the air discharge ducting section is orare angled in relation to the cooling air blower to induce at least onechange in direction in the flow of cooling air therethrough.

Examples of embodiments of the invention are described below withreference to the accompanying drawings, in which:

FIG. 1 is a side view, partly in section on the line I-I FIG. 2, of afirst embodiment of the invention applied to a multi-cylinder injectioninternal combustion engme,

FIG. 2 is a corresponding front view, partly in section on the lineII-II, FIG. 1,

FIG. 3 is a plan view corresponding to FIG. 2,

FIG. 4 shows a detail of this first embodiment on an enlarged scale,

FIG. 5 is a side view, partly in section on the line 'V-V FIG. 6, of asecond embodiment of the invention applied to a single-cylinder internalcombustion engine,

FIG. 6 is a front view corresponding to FIG. 5, partly in section on theline VI-VI of FIG. 5, and

FIG. 7 is a plan view corresponding to FIG. 5.

FIGS. 1-4 illustrate a four-cylinder internal combustion engine ofconventional construction. The cylinders 10a, 10b, 10c, 10d, arearranged upright in a row and are mounted on a common crank case 12. Thehorizontal crankshaft 14, driven by pistons (not shown) in the cylinderscarries a V-pulley 16 at one projecting end 3 and a, flywheel 18 at theother end. Flywheel 18 is equipped with means, for example a drivingflange, for operation of the units which are to be driven by the engine.

Secured on each cylinder is a cylinder head 20a, 20b, 20c, 20drespectively, this head containing valves and associated operatingcomponents, for example injection elements and so on. The elements ineach cylinder head are accessible through a removable cylinder cover22a, 22b, 22c, 22d respectively. The cylinders and cylinder heads, whichare subject to very high operating temperatures, have therearoundcooling fins which are exposed to a flow of cooling air in conventionalfashion. This cooling air flow is produced by a rotary blower wheel 24with blades 24a arranged at its periphery, and it is routed by aconducting or baffle plate 26 so as to flow first along the row ofcylinders and then transversely thereto, that is to say between theindividual cylinders, to be collected at the opposite side and carriedaway. The arrows in FIGS. 1 and 2 illustrate the path of flow of thecooling air. The blower wheel 24 is arranged on a shaft 24b mounted inthe first cylinder a, and it is driven from the wheel 16 through aV-pulley 28.

The channels through which the cooling air flows are lined withsounddeadening means, and to increase 2 their effective length withoutincreasing the dimensions of the engine in the present invention thesechannels (also referred to as muffling passages) are installed asillustrated so as to utilise the free outer areas of the engine.Disposed at the suction side of the blower 24 is a long tubular duct orchannel arranged in the free area between the conducting plate 26 andthe cylinder head covers 22a, 22b, 22c, 22d along the row of cylinders.The admission port 30a of duct 30 is disposed at the flywheel end of theengine so that cooling air drawn in at 300 is first conducted oppositelyto the direction of flow of the cooling air within the conducting plate26, is then given a change of direction of 90 by a bend 30w in duct 30,and finally drawn through blower 24 with another change of direction of90.

The discharge end of the cooling air conducting system is in the form ofa flat, downwardly tapering and downwardly open duct or channel 32 whichis substantially parallel to the line of cylinders. The cooling air frombetween the cylinders is collected here and conducted to atmospherethrough the bottom gap 32a. The exhaust conduits 34a, 34b, 34c, 34d ofthe individual cylinders are connected to an exhaust manifold in theform of a single tube 34 which opens into channel 32 so that the exhaustor combusted gases are conducted away with the cooling air at 32a. (Thetube 34 might also have arranged behind it an exhaust cup of a knowntype for sounddeadening purposes, and this could also be arranged insidechannel or duct 32).

A change in direction of the air flow through about 90 also takes placein channel 32. The silencing effect is still further increased by thechanges in direction of flow within the air conducting system, thishaving been extended to a maximum at both sides of the blower to mufflethe noise.

The ducts 30 and 32 and also the conducting plate 26 are defined byshaped components which conform with one another and can be readilysecured to the engine housing by appropriate means, for example screws.The method of attachment has not been illustrated to avoid confusion ofthe remainder of the drawing. As can be seen from the sectionalillustration, the wall of each of these ducts, for example of sheetmetal, can have a carrying function and support silencing orsoundmuffling media, for example a layer of rock wool, at the sideexposed to the flow of cooling air. This layer is in turn covered by aretaining means, for example a mesh or perforated sheet.

For the sake of simplicity the ducts 26, 30, and 32 are illustrated inFIGS. 1-3 in simple section. lnpractice, however, the wall of duct 26will for example have the cross-sectional form illustrated in FIG. 4.The carrier wall plate 26 is lined internally by a layer 26a of rockwool and this is retained by plate 26b of conforming shape provided withfine perforations. The perforated plate 26b is connected to the wall 26by screws (not shown) and this wall 26 is anchored in turn to the engineblock. The ducts 30 and 32 are equipped and arranged in the same way.

Arranged in duct 26 is a suction tube 36 with ports 36a, 36b, 36c, 36dconnected to the admission ports in the cylinder heads 20a, 20b, 20c,20d. An air filter 38 disposed upstream of the suction tube 36 is soarranged that it takes the combustion air from duct 26 and conducts itto the admission port 361 of suction tube 36. The casing of the airfilter 38, which is of cup form, is connected from the exterior to theend 26s of duct 26, for example is screwed at this end, so that theinlet port to a cylindrical paper insert 36p in this filter communicateswith an annular opening 26ss of duct 26. A contaminant-separator, forexample a cyclone separator 40 of known form with blade walls 400producing a volute effect, is mounted in duct 26 concentrically inrelation to admission port 36! and upstream of port 26ss. Largeparticles of contaminant which may still penetrate into the interior ofthe duct are picked up by the cyclone separator 40 and dischargedthrough a discharge opening 40! in the wall of duct 26.

The combustion air will thus pass from the interior of duct or channel26 through the cyclone separator 40 and through port 26ss into theinterior of air filter 38, to be filtered by the insert 38p andconducted to the central admission port 36t of suction tube 36, which inturn takes care of the distribution to the individual cylinders. Withthe air filter disposed in this way maintenance thereof can be performedfrom the exterior without having to dismantle any parts of the ducts 26and 30.

With the form and arrangement of the admission and discharge ductingsections of the conducting system, i.e. the so-called muffiing passagesupstream and downstream of the blower, in accordance with the presentinvention, these sections have been afforded maximum length and maximumcross-sectional area without making the overall dimensions of the enginelarger than would otherwise be prescribed for it. The muffling passagesbring about a suppression of the noise which occurs in the internalenclosed elements, or is generated by these, with maximum efficiency,allied with a conduction of cooling air. The noise referred to isgenerated for example at the blower 24, at the means 16,

28 for driving the same, in cylinders 10a, 10b, 10c, 10d, in cylinderheads 20a, 20b, 20c, 20d, and in the suction and exhaust parts 36 and24. (The crankcase 12 is equipped with its own individual silencingmeans which have not been shown here, for example baffles). The changesin direction of flow induced by the shaping of the ducting or mufflingpassages confer an advantageous increase in the silencing effect. Thearrangement of the air filter which is accessible from the exterior,

despite taking air from the stream of cooling air, also caters for verysimple servicing.

Reference should also be made to the fact that the air flow is, withadvantage, drawn in at the uppermost part of the engine, namely at 30a,where it has a higher degree of purity. Thus only a quite negligiblequantity of large contaminating particles passes into the cooling airconducting system. The downward air discharge through the gap 32a in thesystem is also of advantage.

The construction and arrangement of the ducting as used in thisinvention for the conduction of cooling air and simultaneoussound-suppression can also be used in single-cylinder internalcombustion engines, as is illustrated by the second embodiment of theinvention illustrated in FIGS. 5-7. In overall construction the engineshown here is similar to that of the engine illustrated in FIGS. 1-4,wherefore like parts in the two cases have been given the same referencenumerals, but in the case of FIGS. 5-7 accompanied by a prime. For thisreason a repeated description of the general construction of the engineis unnecessary.

In FIGS. 5-7 the blower 24 and the cylinder with its cylinder head aresurrounded by a cooling air conducting ducting 126 at the admissionside, and cooling air is conducted through this ducting between and overthe cooling fins at the periphery of the engine parts 10 and 20 andallowed to pass into the discharge duct 132. The exhaust air passes toatmosphere through the bottom gap 132a in this duct 132. Provided at theadmission end is a duct 130 upstream of the duct or channel 126, andthis takes the form of a tubular duct or tube which conducts the air ina volute or spiral path to the blower 24 as clearly seen in FIG. 5. Theadmission port 130a of tube 130 again is here at the uppermost part ofthe engine.

The air filter 138 is secured to the outer wall of duct 126 from above,this making it readily accessible for maintenance. The air passing at126ss from the cooling air stream into the interior of air filter 138passes through the paper filter insert 138p and through the central port136: into the suction tube 136. The exhaust tube 134 here again leads tothe air discharge duct 132.

The spiral or volute form of the admission channel 130 here againprovides a form of construction which secures a maximum length andmaximum cross-section of the cooling and sound suppressing passage atthe admission side. In this second embodiment therefore the sameadvantages are secured with a single cylinder internal combustion enginein relation to the sound suppression, cooling, and the disposal of theair filter, as were obtained in the first example. It is also to bepointed out that in this second embodiment the ducts 126, and 130 and132 are of course also provided with layers of rock wool forsound-deadening purposes, wherefore the wall construction will besimilar to that illustrated in section in FIG. 4.

Finally, it is to be understood that the invention is not limited to theparticular forms of embodiment which have been specifically illustratedand described. In particular the ducting system at the admission end canbe installed in the outer free areas of internal combustion engines ofvarious constructions, and the muffiing passages required can be made ofa form other than that actually illustrated. Moreover other suitablesound-deadening means of known kind can be used in the ducts or mufflingpassages instead of the rock wool described.

What we claim is: 1

1. An internal combustion engine comprising at least one combustioncylinder, a cooling air conducting system including a cooling air blowerassociated with said cylinder, and sound muffling means incorporated insaid cooling air conducting system wherein the conducting systemcomprises an air admission section in the form of tubular ducting whichis disposed round said cooling air blower in spiral or volute formwherein said tubular ducting is provided with an air admission portsubstantially at the uppermost part thereof, and an air filter beingdisposed in the cooling air conducting system.

2. An internal combustion engine according to claim 1 wherein thedischarge side of the conducting system includes a channel disposedclosely adjacent and along said cylinder and extending downwardly alongand adjacent the crank case of the engine, the channel also surroundingthe combustion exhaust pipe of the engine, such that the damping passageon the discharge side is approximately the height of the engine.

3. An internal combustion engine according to claim l-wherein said airfilter is disposed upright in the cooling air conducting system on awall of the latter adjacent the head of the cylinder.

1. An internal combustion engine comprising at least one combustioncylinder, a cooling air conducting sYstem including a cooling air blowerassociated with said cylinder, and sound muffling means incorporated insaid cooling air conducting system wherein the conducting systemcomprises an air admission section in the form of tubular ducting whichis disposed round said cooling air blower in spiral or volute formwherein said tubular ducting is provided with an air admission portsubstantially at the uppermost part thereof, and an air filter beingdisposed in the cooling air conducting system.
 2. An internal combustionengine according to claim 1 wherein the discharge side of the conductingsystem includes a channel disposed closely adjacent and along saidcylinder and extending downwardly along and adjacent the crank case ofthe engine, the channel also surrounding the combustion exhaust pipe ofthe engine, such that the damping passage on the discharge side isapproximately the height of the engine.
 3. An internal combustion engineaccording to claim 1 wherein said air filter is disposed upright in thecooling air conducting system on a wall of the latter adjacent the headof the cylinder.